Two detained aides of a radical Islamic cleric in Pakistan were killed early Saturday when a military convoy carrying prisoners hit a roadside bomb and came under fire in the northwest of the country. The Pakistani military says it is possible the prisoners were the target of the attack.

As soon as news of the attack was reported, there was speculation among Pakistan political analysts and reporters that the prisoners - Muhammad Alam and Ameer Izzat - were killed to prevent them from being interrogated.

"I won't rule out that, whether they were targeted or killed on purpose," Abbas said. "But there could be a possibility of that. But there are a number of daily IED (improvised explosive device) incidents in this area, so maybe this was a targeting the military convoy because the signature (presence) is very huge. Where ever the military convoy is moving, the signature is huge."

Abbas said the prisoners were provided as much security as possible given the circumstances of the region and the resources of the army.

"We cannot ensure complete security or complete protection of the entire area," Abbas said. "And we do not have the kind of equipment which can completely ensure the jamming of the complete area against the IED attacks. So these are common incidents in the area in which our soldiers and officers are also losing lives."

The prisoners were arrested Thursday. Their leader, Sufi Mohammed, was also reported to have been detained this week, but the military denied that report. Mohammed negotiated the failed agreement with the government to impose strict Islamic law in Swat, which was criticized as a capitulation to Pakistan's extremists.

The capture of Alam and Izzat was heralded as good news from Pakistan's security forces, who have claimed key gains in their month-long effort to eject Taliban militants from the region.

But Abbas said that total victory in Swat could only be declared when top Taliban leaders have been killed - something that has not yet happened.